How can I use GoTo Approach to minimize backlash with my Fork arm mount?

November 10, 2008

To minimize backlash with your mount, use your hand control and select Menu – Scope Setup – GoTo Approach. This will let you choose the direction the scope will use when approaching an object during the final part of slewing–the ideal way to minimize backlash.

The directions can be either positive or negative and are defined as seen from the back of the scope. For altitude, positive moves the front of the tube up, negative down. For azimuth, positive moves the front of the scope to the right, negative to the left.

Always set the direction of approach in the opposite direction from the load pulling on the scope. This minimizes effects of backlash in the gear train. The load in altitude is usually because of gravity acting on the scope’s imbalance from accessories (eyepieces and the like). The load in azimuth is due to tracking and is opposite (in reaction) to the tracking direction, so the approach direction will be the same direction as tracking.

Whether to set positive or negative in altitude or azimuth depends on your scope, the type of mount, its orientation, Southern or Northern Hemisphere location and the load from attached accessories.

In a typical situation with Schmidt-Cassegrain (SCT) telescopes, the tube will be back heavy, because you have attached accessories to its back. The load acts to pull the front of the tube up–positive–so the opposite direction–negative–should be chosen for GoTo Approach. For azimuth, the tracking of the scope determines the loading. The telescope tracks to the west–positive (from behind the scope)–so the GoTo Approach should be set to close in from the same direction, moving west–positive.

Many users use the default setting, which is altitude negative, azimuth positive. For the SCT with a star diagonal, GoTo slews will be seen as moving to the up and right with these settings.

In the Southern Hemisphere (from behind the scope), west is to the left, reversing the GoTo Approach settings for azimuth.

Note: when aligning the mount, use the same approach directions to center your alignment stars as you are using for GoTo Approach for the best GoTo performance.

A. Celestron warrants your product to be free from defects in materials and workmanship for two years. Celestron will repair or replace such product or part thereof which, upon inspection by Celestron, is found to be defective in materials or workmanship. As a condition to the obligation of Celestron to repair or replace such product, the product must be returned to Celestron together with proof-of-purchase satisfactory to Celestron.

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Some states do not allow the exclusion or limitation of incidental or consequential damages or limitation on how long an implied warranty lasts, so the above limitations and exclusions may not apply to you.

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Celestron warrants most of its products to be free from defects in materials and workmanship for the product’s usable lifetime to the original owner. Each product will list the warranty for it on the Celestron website.

Celestron will repair or replace the product which, upon inspection by Celestron, is found to be defective in materials or workmanship and within the definitions of the limits described below.

This warranty is effective January 1, 2012, and supersedes all other warranties as noted in brochures, instruction manuals, product packaging, etc.

This warranty does not cover products that have been subject to abuse, misuse, physically damaged, altered, or had unauthorized repairs or modifications. This warranty does not cover defects due to normal wear and tear and other conditions.

Celestron shall use reasonable efforts to repair or replace any binocular or spotting scope covered by this warranty within thirty calendar days of receipt. If it takes longer, the customer will be notified.

If warranty problems arise, or if you need assistance in using your product, contact:

This warranty is valid to U.S.A. and Canadian customers who have purchased this product from an authorized Celestron dealer in the U.S.A. or Canada. Warranty service outside the U.S.A. and Canada is valid only to customers who purchased from a Celestron Distributor or authorized Dealer in the specific country and please contact them for such service.

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Parts or products for which replacement is made shall become the property of Celestron.

Celestron reserves the right to replace any product which has been discontinued from its product line with a new product(s) of comparable function at its sole discretion. Celestron does not issue refunds but only repair or replacement.

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Celestron disclaims any warranties, express or implied, whether of merchantability or fitness for a particular use, except as expressly set forth herein.

The sole obligation of Celestron under this limited warranty shall be to repair or replace the covered product, in accordance with the terms set forth herein. Celestron expressly disclaims any lost profits, general, special, indirect or consequential damages which may result from breach of warranty, or arising out of the use or inability to use any Celestron product. Any warranties which are implied and which cannot be disclaimed shall be limited in duration to a term of one year from the date of original retail purchase.

Some states do not allow the exclusion or limitation of incidental or consequential damages or limitations on how long an implied warranty lasts, so the above limitations and exclusions may not apply to you.

This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

Previous Binocular/Spotting Scope Warranty Information From January 1, 2005, through December 31, 2011, Celestron offered a No Fault Warranty on all binoculars and spotting scopes. For a charge of $25 for binoculars and $35 for spotting scopes, any binocular or spotting scope would be repaired or replaced with the same or similar product at the sole discretion of Celestron regardless of how the binoculars or spotting scope were damaged or rendered unusable. The customer must be the original owner, provide proof of purchase, and return the binoculars or spotting scope prepaid to Celestron.

From January 1, 2003, through December 31, 2004, Celestron offered a No Fault Warranty on the Regal, Noble, and Ultima binocular lines. The details are the same as noted above.

From January 1, 2000, through December 31, 2002, Celestron offered a Limited Lifetime Warranty on all binoculars and spotting scopes. The limitations at that time were similar to wear and tear as noted in the current Limited Lifetime Warranty.

Prior to 2000, Celestron offered a Limited Lifetime Warranty on specific models. Some models had other specific year warranties which have expired.